"Some years ago, the was an intention to demolish the building preparatory to redevelopment and to relocate the Library and the Society. The single factor that stopped this happening was that the mural would have been destroyed, and it was listed for conservation.

No idea whether this is true in whole or part or just folklore.

True the mural is a tad weird."

Firstly, sounds like the archive and the finances of the society were inadvertently saved by the mural. New fancy builds for archives or arts centres seem to have a bad habit of going tits up and costing a bomb (as well as being ugly). Secondly, I rather dig the mural!